Does purring serve some biological or evolutionary function?
purring means that a cat is happy and enjoy it
It attracts humans to cats, and that have certainly worked to the cats' advantage! I can just see a bunch of feral cats in north Africa about ten thousand years ago, discussing whether to go beside humans or stay wild, and deciding to keep the purr as a distinctive ability.
Answers: The original function of purring was to enable a kitten to communicate next to his mother that things are well. A kitten is able to purr by the second time of life, and although he can't meow and nurse at the same time, he can purr and nurse. And the mother cat often purrs backbone, probably to reassure the kitty.
Purring is an integral part of the feline communication system and occurs for diverse reasons. It is classified with the "murmur vocalization" group, which involves sounds produced by a cat while the mouth is closed. In addition to purring, this group of sounds includes grunting, calling, and acknowledgment murmurs. Domestic cats and some feral cats, like pumas and mountain lions (almost any big cat that cannot roar), are all able to purr.
As the cat mature the meaning of the purr changes. Some cats purr to indicate contentment or pleasure, but badly frightened cats and severely poorly cats also purr, and so do females while they are delivering their kittens. It is not uncommon for cats to purr when they are close to death. This final purring may indicate a state of anxiety or possibly euphoria, states that own also been described in terminally ill ancestors.
Animal behaviorists believe that when cats purr under stressful circumstances, they are reassuring or comforting themselves, much as humans may sing to themselves or hum when they are nervous. Frightened cats may purr to communicate submissiveness or non-aggressive intentions. A feral cat may purr to sign that he will not attack and other cats need not feel threatened. Older cats may purr when they play or approach other cats, signaling that they are friendly and want to come closer.
A more recent theory give or take a few purring is that it is caused by the release of nature's own morphine-like substances (endorphins) in the brain. Since endorphins are released under circumstances of aching and pleasure, this would explain the seemingly ambiguous expression of purring. This theory jives with Pederson's reasoning, that purring is initiated in the brain, and is also compatible beside the more mechanical explanations for purring, as endorphins activate one of the main motion systems in the brain (so thought is translated into movement). Whatever the explanation for purring, it seems to indicate cats' contentment and is associated with rise in their affect at times of stress. Purring is one of cats' most endearing qualities.
